Quick methylene blue dye elimination via SDS-Ag nanoparticles catalysts

Methylene blue dye, being toxic, carcinogenic and non-biodegradable, poses a serious threat for human health and environmental safety. The effective and time-saving removal of such industrial dye necessitates the use of innovative technologies such as silver nanoparticle-based catalysis. Utilizing a pulsed Nd:YAG laser operating at the second harmonic generation of 532 nm with 2.6 J energy per pulse and 10 ns pulse duration, Ag nanoparticles were synthesized via an eco-friendly method with sodium dodecyl sulphate (SDS) as a capping agent. Different exposure times (15, 30, and 45 min) resulted in varying nanoparticle sizes. Characterization was achieved through UV–Vis absorption spectroscopy, scanning electron microscopy (SEM) imaging, and energy dispersive X-ray (EDX). Lorentzian fitting was used to model nanoparticle size, aligning well with SEM results. Mie’s theory was applied to evaluate the absorption, scattering, and extinction cross-sectional area spectra. EDX revealed increasing Ag and carbon content with exposure time. The SDS-caped AgNPs nanoparticles were tested as catalyst for methylene blue degradation, achieving up to 92.5% removal in just 12 min with a rate constant of 0.2626 min−1, suggesting efficient and time-saving catalyst compared to previously reported Ag-based nanocatalysts.

of 288.38 g/mol.It was supplied by Sigma-Aldrich, China.Methylene blue (MB) dye was purchased from Al-Nasr Company (Giza, Egypt) and sodium borohydride (NaBH 4 ) was purchased from Research Lab Fine Chem Industries (Mumbai, India).In all of the tests, double-distilled water was utilized.

Synthesis of laser-prepared SDS-capped AgNPs samples
A quantity of 1 × 10 −4 M from CH 3 CO 2 Ag and 1 × 10 −4 M of SDS were dissolved in 100 mL of distilled water using magnetic stirring for about 30 min at room temperature.The produced solution was then exposed to a laser beam for 45 min (sample A02), 30 min (sample B02), and 15 min (sample C02), Table 1.The used Nd:YAG laser operates at the second harmonic generation of 532 nm, with energy per pulse of 2.6 J and a repetition rate of 10 Hz.A volume of 5 mL of the solution in the cuvette was exposed to the laser beam.

Characterization of laser-prepared SDS-capped AgNPs samples
For absorbance measurements, a double beam spectrophotometer, model Shimadzu 3150, with a scanning step of 1 nm in the range from 300 to 700 nm has been used.The surface morphologies of synthesized nanocomposites were analyzed by scanning electron microscopy (SEM) that was conducted on SEM-Sigma 500 VP (Carl ZEISS, Baden-Württemberg, Germany).The chemical or elemental composition of the samples was investigated using a high-energy dispersive X-ray detector integrated into the SEM device (EDX-SEM, AMETEK, Inc., PA, USA).Characterization of Ag NPs using X-ray diffraction (XRD) with Cu-Kα radiation, operated at 40 kV and 40 mA, and a scanning rate of 0.01°/s in the 2θ-range from 5 to 80°, model Philips X'Pert Pro MRD, Malvern, UK.Additionally, dynamic light scattering (DLS) via the Zeta Sizer Nano-series (Malvern, Nano-ZS90, UK) determined the particle size distribution and zeta potential of the Ag NPs.To identify functional groups, Fourier transform infrared (FTIR) spectra were measured using a Bruker Vertex 70 instrument (Bruker, Leipzig, Germany).

Evaluation of catalytic efficiency of laser-prepared SDS-capped AgNPs samples
The laser-produced SDS-coated AgNPs were utilized as catalysts in the reduction process of 2 mL of 100 ppm MB dye by 1 mL of 0.1 M NaBH 4 , conducted in a 3.5 mL cuvette cell at a controlled temperature of 25 ± 2 ℃.
A volume of 20 µL of the previously mentioned catalysts was used in these catalytic reactions.To aid in data analysis, a control test was performed where distilled water was used in place of the catalyst, thereby eliminating any catalytic activity.Absorbance spectra were captured using a UV/visible/IR spectrophotometer (Perkin Elmer, lambda 950, USA), within a wavelength spectrum of 500-750 nm.To avoid any unintended photocatalytic reactions, the solutions, which consisted of MB and the laser-produced SDS-capped Ag NPs, were stored in dark conditions.

Results and discussion
Upon the dissolution of silver acetate and SDS in water at the specified concentration, the solution contains positive silver ions.When this solution is subjected to a laser beam with a high energy level of 260 mJ and a short pulse duration of 10 ns, ionization of the water molecules takes place.This ionization process generates negative electrons.These electrons are subsequently acquired by the positive silver ions, thereby neutralizing them.This process is essentially a reduction of the positive silver ions through electron gain, resulting in the production of neutral silver nanoparticles.

The absorption spectra
Figure 1 shows the optical absorbance spectra of the investigated samples.Note that the absorbance is defined as A = Log (I 0 /I T ), where A is the absorbance, I 0 is the incident intensity and I T is the transmitted intensity, as reported in [41][42][43] .The peak of the three samples occurs at 406 nm that is attributed to surface plasmon resonance of free electrons of Ag metal in the conduction band near the surface of Ag nanoparticles.The absorbance increases with the increase of the exposure time.Sample A02 with an exposure time of 45 min has an absorbance peak of 1.173, while sample B02 with exposure time of 30 min has a peak absorbance of 0.7286.The sample C02 with exposure time of 15 min has an absorbance peak of 0.4591.Figure 1b shows the absorbance peak versus the exposure time.For the silver nanoparticle size calculation in terms of the peak position in the absorbance measurement, the following equation has been used: where D is the modeled effective diameter of silver nanoparticle in nanometer, and λ SPR is the surface plasmon resonance peak wavelength 44 .
The surface plasmon resonance peak wavelength for the three samples occurs at 406 nm.Hence, the calculated particle diameter is 19.8 nm for the three samples.It is noteworthy to mention that the estimated particle size according to Eq. (1) depends only on the peak position in the absorption measurement and does not depend on the full width at half maximum (FWHM) intensity.Experimentally different particle sizes can occur at the same peak absorption wavelength and thus Eq. (1) cannot distinguish between different particle sizes that have the same peak absorption wavelength.For more accurate particle size estimation, another approach has to be used to distinguish between different particle sizes that have the same absorption peak.Mie theory is one of these approaches in which the particle size estimation does not only depend on the peak position, but also depends on the FWHM.It is known that there are two types of broadening, namely, homogeneous broadening and inhomogeneous broadening.When the active species are in a liquid or in a crystal, homogeneous broadening arises and Lorentz function fits well with the absorbing spectra.On the other hand, when the active species are in amorphous solid, inhomogeneous broadening arises and Gauss function fits well with the absorption curve.In the present study, the type of broadening is homogeneous and Lorentz function will be used for fitting the absorption.
Lorentz function has the form: where A( , γ ) is the absorbance as a function of the wavelength λ and the FWHM γ and a is the area under the absorption curve.The area under absorption curve depends on the number of nanoparticle species that absorb light whereas the FWHM γ depends on the lattice defects, impurities, and the scattering between electrons and phonon or between electrons.Figure 2 shows fitting of the experimental data using Eq. ( 2).It appears that there is a good matching between the experimental results and the estimated values from Eq. ( 2).Using Mie theory, the FWHM, γ, is related to the particle modeled effective diameter D through the following equation:  www.nature.com/scientificreports/where b is a constant equal to 0.75 for silver 45 , v F is the Fermi velocity = 1.39 × 10 6 m/s 46 , and γ 0 = V f L ∞ .L ∞ is the mean free path of the electron in a bulk material and is equal to 52 nm for silver metal 45,46 .Hence, γ 0 = 2.67 × 10 13 s −1 .Table 2 shows the modeled effective particle diameter calculated from Eq. (3) using the parameters of fitting the experimental absorption to Eq. ( 2).The values of the particle sizes of sample A02, B02, and C02 are 25.3 nm, 22.8 nm, 23.7 respectively.
For more theoretical analysis, Mie theory has been used and compared to experimental absorbance.There are three optical cross-sectional areas, which are the absorption, scattering, and extinction cross sectional area that is the sum of both absorption and scattering cross sectional area.
These cross-sectional areas are given by the following equation: where σ a , σ s , σ e are absorption, scattering and extinction cross sectional area respectively, and ε 1 , ε 2 , ε m are the real, imaginary, and surrounding medium real dielectric constant, respectively, whereas D is the modeled effective particle diameter and λ is the incident wavelength 47 .
Figure 3 shows these cross-sectional areas for the three samples.The values of real and imaginary dielectric constants as a function of the wavelength are extracted from the work of Jonhnson and Christy 48 .The value of the surrounding real dielectric constant of the medium (water) as a function of wavelength is that used by the work of Meissner and Wentz 49 .The ratio of the absorption cross-sectional area to the scattering cross sectional area is 5.37 × 10 −15 /8.7 × 10 −16 = 6.17 for sample A02, Fig. 3a, 9.28 × 10 −16 /2.06 × 10 −17 = 45.05 for sample B02, Fig. 3b, and 1.3 × 10 −15 /4.9 × 10 −17 = 26.53 for sample C02, Fig. 3c.Hence the smaller the diameter of the particle is, the larger is the ratio of the absorption to the scattering cross-sectional area.Moreover, both the absorption and scattering cross sectional area increase with increasing particle diameter.

SEM images
SEM images of the prepared samples are displayed in Fig. 4. Two magnifications, 10 k and 65 k, are presented.The lower magnification provides an overview of the layer deposited on the glass substrate, while the higher magnification offers detailed information about the particles that constitute the layer.For sample A02, as shown in Fig. 4a at lower magnification, branched microfibers with small particles embedded within them are observed 17 .As depicted in Fig. 4b, a distribution of Ag nanoparticle sizes is evident, ranging from a minimum size of approximately 10 nm to a maximum size of about 60 nm.The most frequently occurring average size . SPR wavelength and calculated particle diameter for the samples using Eq. 3.

Sample name
SPR (nm) γ (nm) γ (s −1 ) × 10   www.nature.com/scientificreports/ is around 30 nm. Figure 5a illustrates this nanoparticle distribution using ImageJ software, with the peak of the distribution occurring at a size of 28.8 nm.Additionally, the full width at half maximum (FWHM) of the distribution is approximately 10 nm.SEM images for sample B02 are presented in Fig. 4c, d.The lower magnification reveals particles deposited on the substrate, forming a flower-like structure.The higher magnification displays the particles that constitute this structure, with sizes ranging from a minimum of 4 nm to a maximum of 24 nm, and an average particle size of about 14.7 nm. Figure 5b depicts the particle size distribution of sample B02, with the most frequently occurring average particle size at 14.5 nm.The FWHM for this distribution is about 5 nm, indicating a better particle uniformity for sample B02 compared to sample A02.
In sample C02, as depicted in Fig. 4e, the deposited layer forms a continuous film with random grain sizes.In Fig. 4f, small particles with certain distributions are observed.Figure 5c presents this nanoparticle diameter distribution for sample C02.The distribution reveals smaller particles of about 7 nm up to larger particles of about 29 nm, and the peak of the distribution occurs at around 15 nm.The FWHM of this distribution is 4 nm, suggesting a better uniformity than that of samples A02 and B02.This condition corresponds to shorter exposure time to laser beam compared to the other two samples.

EDX analysis
Electron dispersive X-ray spectroscopy (EDX) has been employed for both qualitative and quantitative analyses.This technique has enabled the identification of several elements, including Ag, Na, S, and Carbon.The EDX spectra for the samples are depicted in Fig. 6.A peak, indicative of Ag, is observed at 3 keV 35 , and this is consistent across all samples.Other elements, specifically Na, O, C, and S, are also evident in the spectra.These elements are attributed to SDS.For a comprehensive quantitative analysis, Table 3 provides both the atomic and weight percentages of these elements.The table clearly shows that the Ag content in sample A02 is higher than that in B02 and C02.The weight percentages of Ag/Na are 1.378, 0.776, and 0.048 for A02, B02, and C02, respectively.In essence, a decrease in the exposure time of the samples to the laser beam leads to a reduction in the Ag/Na ratio, suggesting an increase in SDS capping.This observation is consistent with the findings from the SEM images and is corroborated by the UV-visible absorption spectra shown in Fig. 1.The C content is also highest in sample A02 compared to B02 and C02.Conversely, O and Na have the lowest content in sample A02 compared to B02 and C02.www.nature.com/scientificreports/

DLS and zeta potential
Figure 7 (left) shows dynamic light scattering (DLS) of sample A02.The first peak occurs at 32.7 nm.Using SEM images described in Sect "SEM images", the most frequently occurring average size is around 30 nm.As shown in Fig. 5a for sample A02, the peak of the particle distribution occurs at 28.8 nm, which is close to the results of this DLS measurement.Figure 7b shows DLS of sample B02.The dominant peak occurs at the vicinity of 20 nm.The most frequently occurring average size using SEM images described in Sect "SEM images" is in the vicinity of 15 nm, which is close to the result of DLS measurements.Unlike the other two figures, Fig. 7b exhibited a secondary lower intensity peak at 3.4 nm. Figure 7c shows DLS of sample C02.The dominant peak occurs at 43.2 nm.Using SEM images described in Sect "SEM images", the size reaches 29 nm.
The zeta potential describes the surface potential on the particles in colloidal solution and the stability of the nanoparticles against agglomeration.The values of the zeta potential for samples A02, B02, and C02 are − 17.9, − 17.5 and − 16.4 mV.The negative sign means the charge on the surface of the particle is negative.This leads to repulsion force between these nanoparticles to prevent agglomeration and making stability for the particles.The higher is the zeta potential, the more stable are the nanoparticles.Several studies have reported smaller magnitude of zeta potential.For instance A. Singh et al. used Ag nanoparticles to overcome hepatocellular ailments with zeta potential of − 11.3 mV 50 .

X-ray diffraction
The XRD was measured in the range of diffraction angle from 5° to 80°.It presents the crystalline size and the structure of the SNPs that are characterized by the observed peaks (Fig. 8).The distinct diffraction peaks of the 2Ɵ values of 27.81°, 32.16°, 38.12°, 44.3°, 46.21°, 54.83°, 57.39°, 64.42° and 77.45° are indexed to (210), ( 122), (111), ( 200), ( 231), (142), (241), ( 220) and (311) planes correspond to a face-centered cubic structure (fcc) and are crystalline in nature 51,52 , (JCPDS file no.84-0713 and 04-0783).There is an increase in the relative intensity of the peaks as the laser exposure time increases and there is a shift toward a lower 2Ɵ value that could be due to the change in the structure of the formed SNPs.www.nature.com/scientificreports/

FTIR spectra for SDS-AgNPs
Infrared absorption measurements were conducted using a FTIR spectrometer in the range of 4000-400 cm −1 .The spectra were measured in transmission mode.Figure 9 shows the FTIR spectra of the SDS capped AgNPs samples, A02, B02, and C02.The spectra depict, for sample C02, absorption peaks at 3267.0, 1637.4,1398.2, 1245.9, 1062.7 and 597.9 cm −1 .The peaks correspond to O-H stretching [53][54][55][56] , N-O stretching 56 , N=O stretching 53,54 , SO2 asymmetric stretching 48 , S = O stretching [55][56][57] , and C-H bending 53,54,58 .The peak 3267.0 is red-shifted by 61.7 cm −1 to be 3328.7 cm −1 for sample A02 and shifted by 59.9 cm −1 to be 3326.8cm −1 for sample B02.A peak at 2352.9 cm −1 , absent in sample C02, appears in the spectrum of the sample A02, while it has a shift for the sample B02 to appear at 2350.9 cm −1 .This peak was attributed to C=O stretching 59 .The peak 1637.4 cm −1 appears at the same frequency for all samples.The peaks 1062.7,1245.9, and 1398.2 are red-shifted by 52.1, 61.8, and 57.8 cm −1 for sample A02 to become 1010.58,1184.2, and 1340.4 cm −1 , respectively.These peaks for sample C02 are also red shifted by 53.8, 59.8, and 57.8 cm −1 to be 1008.85,1186.1, and 1340.4 cm −1 , respectively.Finally, the peak of sample C02 at 597.9 cm −1 is red shifted by 5.98 cm −1 for both samples A02 and B02 to become 603.7 cm −1 .The shift of peaks particularly the 1063 cm −1 and 1246 cm −1 that is related to SO2 molecule indicates capping of silver NPs by SDS as the single compound of SDS has specific fingerprint peaks at 1080 cm −1 and 1247 cm −1 that

The catalytic activity of SDS capped-AgNPs
The catalytic activity study of the laser-irradiated samples was performed at room temperature (25 ± 2 °C) using the reaction of MB dye with sodium borohydride in dark conditions, following amended method reported elsewhere [62][63][64] .That is, the laser-synthesized SDS-capped AgNPs catalytic activity was examined for the reduction of aqueous MB to Leuco-MB in the presence of excess NaBH 4 .The A02, B02, and C02 SDS-capped AgNPs' catalytic efficiencies have been investigated and compared with noncatalytic ones.In the noncatalytic reaction, 2 mL of MB (100 ppm) was mixed with 1 mL of 0.1 M sodium borohydride.
In the case of the catalytic reaction using 3.5 cm 3 cuvette, 1 mL of 0.1 M NaBH 4 was used to examine the catalytic reduction of 2 mL of highly concentrated MB (100 ppm) by 20 μL of laser-synthesized SDS-capped AgNPs aqueous solutions from A02, B02, and C02 samples.The absorption spectra for the catalytic reactions by A02, B02, and C02 catalysts at different time intervals are shown in Fig. 10a, b, c.The absorption spectra display two peaks at 615 nm and 665 nm.The 615 nm peak is a shoulder peak for the maximum wavelength (λ max ), while the 665 nm peak is MB's highest absorption peak in aqueous solutions.The 615 nm peak is a high-energy band associated with a vibronic transition, and the 665 nm peak corresponds to n-π* transitions.The reduction process was found to be accelerated in the presence of our catalysts which showed a rapid reduction in the absorption intensity at 665 nm of MB solution within 12, 23, and 27.5 min, for A02, B02, and C02, respectively as shown in Fig. 10a, b, c.It was previously reported that Ag NPs generally help in the electron relay from BH The MB removal percentages (Removal%) have been determined using Eq. ( 7) utilizing the absorption peak at 665 nm.
where A o represents the initial absorbance at time zero, and A s corresponds to the absorbance of the sample at a specific time.The results of catalytic MB removal% versus reaction time are presented in Fig. 10d, e, f for A02, B02, and C02 SDS-capped AgNPs, respectively.Also, the rate constant of the reaction has been determined from applying the nonlinear form of the first order kinetic model, Eq. ( 8), as shown in Fig. 10g, h, i for A02, B02, and C02 SDS-capped AgNPs, respectively.
where k app (min −1 ) is the rate constant for the dye removal reaction and t (min) is the reaction time.
Table 4 shows values of MB removal%, optimized time, K app and ratios of K apps ' in the presence and absence of our SDS-capped AgNPs catalysts.The absorption peak at 665 nm for MB dye was found to decrease rapidly in the case of A02 NPs with an increase in the reaction time to 12 min.The removal% reached about 92.52% (Fig. 10d) with a rate constant of 0.2626 min −1 (Fig. 10g).The spectra in Fig. 10b, c indicate that the MB dye has been degraded at a lower rate within 23 and 27.5 min, in the case of B02 and C02 catalysts, respectively.For B02 SDS-capped AgNPs, the removal% reached about 91.02% (Fig. 10e) with a rate constant of 0.09016 min −1 (Fig. 10h).Whereas removal% of 92.28% (Fig. 10f) and a rate constant of 0.07081 min −1 (Fig. 10i) were reached using C02 catalyst within 27.5 min.Based on the data presented in Fig. 11a, it can be observed that the noncatalytic reaction resulted in a removal percentage of 3.7% within a time frame of 300 min.Additionally, the kinetics of this reaction can be modeled using a pseudo-first-order approach, with an apparent rate constant k app ' of 0.000196 min −1 as depicted in Fig. 11b.It is worth noting that this rate constant indicates an exceptionally slow rate of removal for a high concentration of MB, suggesting a sluggish non-catalytic reaction.
The rate of increase for the catalytic removal of MB can be determined by using the equation proposed by Alfryyan et al. 63 .
The catalytic rate of increase reached ~ 1337, 459, and 361 for A02, B02, and C02, respectively, relative to the noncatalytic reaction.The findings indicate that the A02 reaction exhibited the fastest reaction rate among the tested catalytic reactions when subjected to a high concentration of the MB dye.This could be attributed to the fact that the A02 sample contains the largest quantity of the AgNPs and the smallest ratio of SDS compared to the B02 and C02 samples, as previously suggested by the absorption spectra in Fig. 1a and EDX spectra and their analysis in Fig. 6 and Table 3. Whereas the ratios of Ag/Na weight% reached 1.378, 0.776, and 0.048 for A02, B02, and C02, respectively.That is, as the laser exposure time extended to 45 min, the rate of MB dye removal in the A02 sample increased, which corresponded to a rise in the concentration of elemental silver.Also, the differences in the micro and nanomorphologies as shown in Fig. 4 may affect the surface area and hence affect the catalytic performance.The observed decrease in the B02 and C02 samples could potentially be due to the inhibitory effect of SDS, employed as a capping and stabilizing agent, on the catalytic activity of the AgNPs.This inhibition could be a consequence of the electrostatic attraction between the AgNPs and SDS.Based on our investigation into the impact of alkaline and acidic conditions on the degradation of methylene blue (MB) using the optimized SDS-capped AgNPs sample, as shown and described in the supplementary data (Fig. S1), we observed that degradation efficiency decreases under acidic conditions but improves in alkaline conditions.In other words, pH significantly influences the degradation process.Alkaline conditions enhance MB degradation, while acidic conditions hinder it.These findings align with previously reported data by Perera et al. 66 .Our optimized SDS-capped AgNPs sample that was prepared at 45 min demonstrated a high efficiency in the catalytic degradation of methylene blue (MB) dye, achieving 92.5% dye removal in just 12 min with a rate constant of 0.2626 min −1 .In comparison to other AgNPs-based catalysts synthesized via green routes (as indicated in Table 5), the performance of our designed catalysts stands out significantly 62,[67][68][69][70][71] .For instance, a study uses l-histidine capped silver nanoparticles (His-AgNPs) for the degradation of MB dye, reported 98% dye removal in 40 min 72 .Another research utilized marine algae-mediated silver nanoparticles (AgNPs) for the degradation of MB, reported process completion in 20 min with a rate constant of 0.106 min −173 .In another study, AgNPs were loaded on polyvinyl alcohol sponges, which showed a rate constant of 13.7 × 10 −3 s −1 for MB reduction 74 .Lastly, research that used in-situ fabricated AgNPs on TiO 2 for 4-nitrophenol reduction reported a rate constant as high as 394 × 10 −3 s −175 .In conclusion, our optimized SDS-capped AgNPs sample shows a promising performance in terms of both reaction time and efficiency when compared to other AgNPs-based catalysts reported in the literature.This highlights the potential of our method for industrial applications, particularly in sectors requiring efficient dye degradation.

Conclusion
SDS -capped Ag nanoparticles of varying sizes were synthesized using a pulsed Nd:YAG laser at 532 nm at different exposure times.The nanoparticle sizes, confirmed by SEM images, were modeled using Lorentz fitting to the experimental absorption data.The estimated sizes were 25.8, 22.3, and 23.7 nm for the three tested samples.EDX analysis verified the presence of silver nanoparticles in accordance with the absorbance spectra for silver content.As laser exposure time increased up to 45 min, the content of silver and carbon rose, while oxygen and sodium decreased.The synthesized SDS-Capped AgNPs showed promising results in catalysis, with the sample that was prepared at 45 min achieving 92.5% MB dye removal in 12 min at a rate constant of 0.2626 min −1 .The samples that were prepared at exposure times of 30 and 15 min demonstrated slightly lower rates, achieving around 91-92% dye removal within 23 to 27.5 min, with rate constants of 0.09016 min −1 and 0.07081 min −1 , respectively.Extrapolating on the current results, we anticipate that sample exposure to laser for further prolonged time would results in complete MB removal at higher rate.These findings hold significant industrial implications, particularly for sectors requiring efficient dye degradation, such as textile and water treatment industries.The high efficiency and speed of dye removal demonstrated by the synthesized silver nanoparticles could lead to cost-effective and environmentally friendly solutions.Looking ahead, further optimization and scaling of this method could pave the way for its broader adoption in various industrial applications.Additionally, exploring the potential of these nanoparticles in other catalytic processes could be a promising direction for future research.

4 (Figure 1 .
Figure 1.(a) Absorbance spectra and (b) maximum absorbance versus exposure time of SPR modes of Ag NPs for the samples A02, B02, and C02.Circles represent experimental data, whereas the solid line presents linear fitting.

Figure 11 .
Figure 11.(a) Removal % of MB in the non-catalytic reaction and (b) their first order kinetic modeling with k app of 0.000196 min −1 .

Table 3 .
Quantitative elemental analysis using EDX for the samples.

Table 4 .
Schematic reaction of MB dye reduction using NaBH 4 in the presence of SDS-capped Ag NPs catalyst.Data obtained from the catalytic MB degradation in the absence and presence of our SDS capped-AgNPs catalysts.

Table 5 .
Comparative analysis of our designed catalysts and AgNPs-based catalysts synthesized via green routes.